HTML email builds an email that survives email clients — the table-structured, inline-styled markup the ancient renderers need, checked at email-client widths and exported ready to send. It's the template for the format where modern CSS goes to die.
What an email run builds
Brief it like a campaign — "a launch email for the new tier: headline, three features, one button, footer" — and the agent builds the email: header, body blocks, call to action, footer, all in client-safe markup. The result opens in the email viewer: the message at email-client width, as it will render.
Email clients are not browsers — Outlook still renders Word HTML, Gmail clips long emails, dark mode inverts colors you didn't set. The template builds for that reality: tables over flexbox, inline styles over stylesheets, fallbacks over features.
HTML email · Devin · e2e · gate PASS
The Launch Email — The announcement email for this very product — one clear CTA, inlined tables, dark-mode safe.
▸ the prompt that made it▾ the prompt that made it
“Design an HTML email: a launch announcement for a desktop design tool — one clear CTA.”
Client-width checking
The viewer shows the message at the widths real clients use — a narrow inbox pane, a mobile mail app — so the design reads at the size it's actually read. The gate checks email rules: image fallbacks, table structure, safe fonts.
Steering an email
Same steering as any result:
- ⌥-click a block, comment on the exact spot ("the button should feel heavier")
- Follow-ups for structure ("add a PS under the footer")
- Tweaks for the parameters — accent color, density, image size
- Versions — one take with a hero image, one text-forward
What it's good at
- Launch and campaign emails — the announcement that has to look right
- Newsletters — the recurring layout, readable in every client
- Transactional design — the receipts and welcomes that carry the brand
- Email templates — a base for a campaign series
Exporting
Emails export as HTML — the client-safe markup ready to paste into a sender — and PNG for a visual check or a design doc. The files stay in the project for the next campaign or the next take.
Tip: Say "client-safe" in the brief even though the template enforces it — it keeps follow-ups from drifting back toward modern CSS an Outlook renderer will strip anyway.